Friday, 31 May 2019

Creality printers, their cooling fans and ducts Part 2

Chuck just released a follow up to the fan duct video that this blog post was discussing.

His main point I think, was that his Cura profile for pla made the most difference. He is most likely right about this as the video evidence shows and you can't fault him for this. He goes on to talk about Chris Riley and his own follow up video about Chucks results, and posits other takes on what is going on.

Chris uses tape to block the flow and this was one of the options I suggested in Part 1. I didn't even consider tape for it in this location though, I was thinking to place it over the bottom third of the face of the fan for testing lol.

My mind was stuck on designing and making a solid set of partitions for everything. D'oh!
(Slowly licks closest window, while
drooling heavily lol)

My own issue and focus still, is that if you're only printing pla then you probably wont need to take this research any further. My continuing issue with it, is that profiles etc, dont always translate over to other filaments like petg that are often fussed over in trying to get them correct and string free, and I suspect this applies to other types of filament as well.

Not being able to control what and where things are being cooled limits you and reduces the control you have over the process.

You only need to look back to how the Prusa extruder is set up and how it works with target specific fans doing different jobs individually. This gives you more control, and I prefer this thought process.

I haven't looked at the
Hero Me Fan Duct closely yet, but will find it and link to it in here so everything is together.

Here is the general search on Thingiverse on the "Hero Me by
mediaman" as there are a number of revisions and versions with extras etc

Here is the OEM or original Creality extruder setup with a leveling probe allowance.

Here are the two I'm thinking of as they match whats going on in my addled brain atm

I think the only thing to do at this point is to print the Hero Me files and test it out on my rig, and test some petg with stringing tests, to see how well it works.

I also have some spare e3d v6 direct drive setups and a Titan extruder that I could take off one of the other printers. One is already half disassembled right now anyway, and make a design for them, but lets not have another unfinished project laying around right now lol

Wednesday, 29 May 2019

Creality printers, their cooling fans and ducts Part 1

A few weeks ago I watched Chuck Hellebucks YouTube video about whether you need a cooling fan on a Creality 3d printer.

He discovers that the heat Heat Sink cooling fan, as opposed to the part cooling fan, is doing more than is asked of it and the overflow of this fan is cooling your part to the point that your part cooling fan isn't really needed.

As you can see in this picture the front fan at this size is covering not just the heat sink but is also blowing on the heat block as well. You really dont want this as it cools your heat block, which is a bad thing, making it difficult to trust your temperature settings, along with forcing your printer to compensate unnecessarily for it.

It isn't difficult to see that the overflow of air from this will also be hitting the part being printed as well.

This is not a good thing and a bad design choice as it takes away any control from you, and makes adjusting settings very difficult.

In the following pictures you can see a Prusa mks 2.5 extruder housing with the components they use, and the layout they chose as well.

The smaller Heat sink fan (On the left) is only blowing onto the Heat sink and the overflow isn't providing the same amount of interference to the part as the Creality. (Some overflow would be expected though)

The much larger part cooling fan with its directed duct on the front (In this case a modified duct to surround the part a lot more)

I'm not sure if you can make it out in the next photo of the Prusa clone, but the heat block itself isn't really receiving any direct air from either fan.

The problem with the Creality setup....

Is that the excess air being blown over your part, makes it difficult to control each aspect of the printing process. If you can control all aspects of the process then you have options where you can adjust and fine tune your print process.

In the following example I used my experience of my old i3 in setting up some (Very old, and had to dry is for 2.5 hours at 65) petg, to print a new duct for my CR-10 in order to try and take back some control of this process.

As you saw in the previous pictures, I modified my old Prusa i3 clone thing, with their extruder setup and found that with this, I could cool petg a little on about 20% to help with stringing and it worked really well after testing some settings.

Unfortunately the CR-10 forced me to turn off the part cooling fan altogether, and despite doing this, the Heat Sink cooling fan, was blowing all over my print causing it to lift away from the bed causing it to warp up.

Controlling stringing would have been a bloody nightmare on a lot of other more complex and larger prints as well. So we need to find a solution to this.

This tiny little part was always going to be the small kid, picked on by the school bully, and sure enough, even with the part cooling fan turned off, the part warped.

The section that did warp was a victim of its own design and too many years of experience in the back on my mind, niggling at me telling me it probably would.

Apart from turning off your part cooling fan the thing you can do to help with this, is to re-orient the part that is most likely to warp, to be facing away from the front of the fan and bed (Not always possible though).

So rotate to avoid the aggravate :-)

This warping isn't excessive either, and could also be fixed with a heat gun and a flat surface. The point of all this though, is that I dont have the control I had before, and don't like this one little bit.

Once the new part cooling fan duct is attached to the printer (Printed in White Petg here) you can see where it lifts from the side. In this case and only good thing about this, it is better than it pointing down into the path of the printed part threatening to knock the print off the bed the moment you walk away.

The question is "What do I do, to fix this?"

1. Use a smaller fan similar to the Prusa and to model a modified mount that fits the existing steel housing for it.

Block off some of the airflow along the bottom of the fan so it doesn't blow onto the heat block ie some kapton tape, placed across the bottom 1/3 of the fan. ???3. Block off the two fans with partitions so each one is only blowing where we need it.

3. Redesign a brand new metal shroud to accommodate the smaller Heat Sink fan and redesign the old part cooling fan with a better duct and fan.

4. Nothing, leave it alone.

My procrastination skills are "5th Dan black belt" so don't hold your breath waiting for me to solve this in a short amount of time, but I would like to take some control back over the decisions I make about setting up a print rather than being dictated to by this crappy design.

I'm not
really asking for suggestions, look upon this as talking to myself and putting the redesign idea out there for others to take up this challenge. I will come up with a decision and design sooner or later.

Will test the new duct later. Here is the link to the Thingiverse file I chose.

Sunday, 12 May 2019

Motion Activated Light Strip

While wandering around Aldi the other day, I spotted some $12.00 led motion activated light strips and decided they might come in handy.

Download the files here along with a 20x20 end cap

I added another light tray for 10mm strips so it is about 30mm wide internally.
The original one suits 8mm wide strips.

I decided to place them somewhere on the crossbar on my CR-10 and took the obligatory measurements and committed a design to paper. 

I made a simple rectangular box to house the 8mm x 330mm pieces I cut down from the single 1m length of lights. I printed diagonally as it was decided to give the housing a final length of 360mm as it was a good size to fit on the bed and house the lights.

They fit comfortably, but I needed to figure out how to best route the wires.

A friend of mine Adz, inspired me through a close friend of his, Spiro, so I just ran it down and around the frame ;-D

I soldered the cut down strips together and am here to warn you about getting the domed clear covering hot, as it gets sticky AF and messy.

It will be mounted to the front of the cross bar so I trimmed down the silver trim on the printer to make room for the strip.

I modeled some T-Nuts about 12mm long to slide into the cross-bar to which the strip would be glued later.

I forgot to add some z-hop and ended up printing these 3 times as they kept getting knocked over lol

The T-Nuts slid into position. They were tight and hard to slide in, where the upright was attached to the cross-bar, but lose along the length of the bar ?? I think the screws joining the Aluminium together might be tight enough to be slightly squishing the bar.

To make this easy I used some spring clamps to hold a piece of thin MDF along the bottom of the bar to help with lining everything up. The idea was to place a drop of CA glue on each T-Nut and then sit the bar on that and just slide back and stick to the glue.

Tada !!!

Once the glue had set up I slid the bar out and hit it with some activator just to be sure :-)

The battery pack comes with some double sided tape so I mounted it on the bottom of the cross-bar and set it to come on automatically.

The silver warning tag really reflects the light which itself could be stronger but a battery power strip of lcds was never going to be really powerful.

Over all I'm quite happy with it and it comes on when I'm near or when the bed and print head are moving and turns itself off when it isn't.